This case illustrates a very common problem in ultrasound. Finding an unusual finding tends to paralyze our search for more findings. This 20-week fetus was referred for an anomaly on the right of the face. The following sets of images display the right face, and after the left face. There are also 3 video-clips: the right-side of the face (1 MB), a second (different) clip of the right-side of the face (400kb), and the left-side (700kb). I drew some little puppets for orientation, but the video-clips are easier to review.

Right side of the face and the associated video clip demonstrated a "skin tag" along the right mandible.

After delivery the skin tag is faintly visible (note the arrow)

The frontal view of the face demonstrated some micrognathia (which was not appreciated prenatally). Note how in this view the mandible is not seen.

The left side of the face demonstrated a misshapen ear. Note the remarkable similarity between the 3D rendering and the postnatal view.

That last image is actually a 3D reconstruction. It was originally a regular video-clip obtained a few years ago. The clip was imported in a program called Sonocubic and 3D reconstructed. Pretty neat since this was no special transducer, and the acquisition had not even been performed in view of obtaining a 3D volume.

Questions & answers

This is most likely an simple skin tag, but in the context of ear anomalies it could also represent melotia (or an accessory ear lobe see Ear anomalies for definitions)

The left ear in malformed (click here for a review of Ear anomalies). It has a misshapen lobe and helix 

As you look on the left side the mandible is not properly visible in the side of the face. It is "too recessed" due to unilateral micrognathia. Compare the view of the right side of the face. And this was quite subtle: this mandible was asymmetrically hypoplastic.

So the syndrome we were looking for was a syndrome that associate facial asymmetry and ear malformations. Using these keywords in OMIM provided only 6 entries:

#107480 TOWNES-BROCKS SYNDROME; TBS
#101400 SAETHRE-CHOTZEN SYNDROME; SCS
*176943 FIBROBLAST GROWTH FACTOR RECEPTOR 2; FGFR2
314600 WILDERVANCK SYNDROME
141400 HEMIFACIAL MICROSOMIA WITH RADIAL DEFECTS
164210 OCULOAURICULOVERTEBRAL DYSPLASIA

of which the last one oculoauriculovertebral dysplasia or Goldenhar syndrome. I apologize for cruelly post another case of Goldenhar syndrome during the test period... this was a small incentive for those who review all the new cases and give them a small advantage, and clearly several astute readers recognized the similarity of the two cases.